The honeybees that pollinate one-third of Americans’ daily diet are dying, and in the eyes of some environmentalists, one culprit may be a decades-old Environmental Protection Agency system.

The system, called “conditional registration,” is essentially a way to get pesticides on the market quickly. But to environmentalists and some experts, it has become too loose, letting potentially dangerous pesticides on the market, and letting some stay there too long.

Insecticides conditionally registered in the early 2000s have been blamed for impairing honeybees’ immune systems; in the past five years, the honeybee population has declined 20 to 30 percent each year, according to the U.S. Department of Agriculture.

“To continue to risk the collapse of our honeybee population and other insects that support our ecosystems is a tragedy,” said Jonathan Evans of the Center for Biological Diversity, a national environmental advocacy group.

The criticism of the EPA’s conditional registration system is nothing new. A Government Accountability Office report from August, for example, said the agency has a confusing record-keeping system for tracking pesticides — a problem the GAO first flagged in 1986. The recent report helped revive claims that conditional registration is unsafe.

“I think it’s really concerning that they have acknowledged that they have all these problems and missing data, but they are still trying to go full steam ahead,” said Mae Wu, an attorney at the Natural Resources Defense Council, another advocacy group.

For its part, the EPA said its 2012 review showed that record-keeping troubles have not affected the safety of products it has approved.

The EPA also said it was taking steps to improve the tracking of pesticides, seeking to “promote consistency and enhance transparency” of its system.

The conditional registration system began in 1978 with an amendment to the law that governs insecticide use. It allows some pesticides to be sold before all necessary studies are completed, as long as the company follows up with required data by a designated date, the pesticide will not cause “any unreasonable risk to the environment” and “the use of the pesticide is in the public interest,” according to the EPA’s Web site.

About 16,000 pesticides are registered with the EPA, and each manager in the agency’s Office of Pesticide Programs is responsible for keeping track of about 800.

But without a centralized system, managers monitor their products in different ways — with spreadsheets, handwritten notes, or just by memory, said Alfredo Gomez, director of the GAO’s natural resources and environment division.

As a result, the GAO found that the EPA is unable to provide accurate information on the number of conditionally registered products. (The NRDC and the EPA have said that about two-thirds of pesticides are conditionally registered, although the flawed record keeping makes it difficult to confirm that number.)

In response to the most recent GAO report, the EPA has again promised to better track conditional registrations. But experts at top environmental watchdog groups say they are worried about the EPA’s ability to follow through on those promises, and they also believe that the EPA has overused conditional registration altogether in approving pesticides.

When questioned about conditional registration, the EPA said that its internal 2012 analysis “did not show the agency’s past use of conditional registrations was inappropriate,” only that its “tracking system was inefficient and confusing.”

In 2003, Bayer CropScience received conditional registration for clothianidin, a type of neonicotinoid. Neonicotinoids are insecticides that target the central nervous system in insects; they were introduced as an alternative to other pesticides that are more toxic to humans and wildlife, according to the EPA.

Bayer followed up with more data in 2007 about how clothianidin affects pollinators — three years late, according to the NRDC. EPA reviewers determined that Bayer’s study had structural flaws but classified it as “supplemental,” meaning they thought it provided some scientifically sound information but did not follow testing protocol, according to a 2011 letter posted on the EPA’s Web site from the director of the Office of Pesticide Programs, which responds to concerns about clothianidin.

Still, clothianidin was switched to full registration in 2010.

“The EPA is not aware of any data demonstrating that bee colonies are subject to elevated losses due to long-term exposure to this compound,” the agency says on its Web site. The USDA said that the science on colony collapse disorder is unclear and could be because of several factors, and that neonicotinoids are only one possibility. It said that the students who “reported a negative impact on honeybees by neonicotinoids relied on large, unrealistic doses and gave bees no other choice for pollen, and therefore did not reflect risk to honeybees under real-world conditions. “

In a statement, Bayer said: “There has been no demonstrated effect on bee colony health associated with the proper and labeled use of neonicotinoids.”

Even so, the European Commission voted recently to severely limit or ban three major neonicotinoids across most of Europe for two years while it studies the issue. In addition, beekeepers and environmental and consumer groups joined forces in a lawsuit against the EPA, for its failure to follow the lead of European officials.

Although the GAO cited the history of clothianidin and nanosilver, the purpose of its report wasn’t to evaluate the pesticides — only to assess the EPA’s record keeping. But the GAO did make three recommendations to the EPA to improve its record-keeping system and Web site, which the GAO said contains inaccurate information about conditional registration.

The EPA said it has recently updated its Web site with clearer content.

Comments our editors find particularly useful or relevant are displayed in Top Comments, as are comments by users with these badges: . Replies to those posts appear here, as well as posts by staff writers.

To pause and restart automatic updates, click "Live" or "Paused". If paused, you'll be notified of the number of additional comments that have come in.

Comments our editors find particularly useful or relevant are displayed in Top Comments, as are comments by users with these badges: . Replies to those posts appear here, as well as posts by staff writers.